> auto m2 = m; // implicit too
  Taking a copy requires making an allocation.

C++ makes it “look nice” at the cost of clarity. But not consistently. Overall, despite addition of syntax sugar in various places to make things look smooth, we arguably have “a lot of syntax” (“syntax castles”) in C++, as a result of embracing a lot of complexity. C, OTOH, avoids both sugar and castles.